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Histone acetyl transferase 1 is essential for mammalian development, genome stability, and the processing of newly synthesized histones H3 and H4.

Nagarajan P, Ge Z, Sirbu B, Doughty C, Agudelo Garcia PA, Schlederer M, Annunziato AT, Cortez D, Kenner L, Parthun MR - PLoS Genet. (2013)

Bottom Line: Murine Hat1 is essential for viability, as homozygous deletion of Hat1 results in neonatal lethality.The neonatal lethality is due to severe defects in lung development that result in less aeration and respiratory distress.Many of the Hat1(-/-) neonates also display significant craniofacial defects with abnormalities in the bones of the skull and jaw.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, OH, USA.

ABSTRACT
Histone acetyltransferase 1 is an evolutionarily conserved type B histone acetyltransferase that is thought to be responsible for the diacetylation of newly synthesized histone H4 on lysines 5 and 12 during chromatin assembly. To understand the function of this enzyme in a complex organism, we have constructed a conditional mouse knockout model of Hat1. Murine Hat1 is essential for viability, as homozygous deletion of Hat1 results in neonatal lethality. The lungs of embryos and pups genetically deficient in Hat1 were much less mature upon histological evaluation. The neonatal lethality is due to severe defects in lung development that result in less aeration and respiratory distress. Many of the Hat1(-/-) neonates also display significant craniofacial defects with abnormalities in the bones of the skull and jaw. Hat1(-/-) mouse embryonic fibroblasts (MEFs) are defective in cell proliferation and are sensitive to DNA damaging agents. In addition, the Hat1(-/-) MEFs display a marked increase in genome instability. Analysis of histone dynamics at sites of replication-coupled chromatin assembly demonstrates that Hat1 is not only responsible for the acetylation of newly synthesized histone H4 but is also required to maintain the acetylation of histone H3 on lysines 9, 18, and 27 during replication-coupled chromatin assembly.

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Related in: MedlinePlus

Hat1 is essential for maintaining genome stability.A) Hat1+/+ and Hat1−/− MEFs were stained with either DAPI or α-γH2AX antibodies as indicated (left). Visible γH2AX foci were counted in 12 cells of each genotype (right). B) Metaphase spreads from Hat1+/+ and Hat1−/− MEFs were analyzed for chromosome number and the presence of breaks and fusions. The percentage of cells containing the indicated chromosomal abnormality is given. The number of spreads analyzed was 56 (Hat1+/+) and 112 (Hat1−/−). C) Metaphase spreads were generated from Hat1+/+ and Hat1−/− MEFs. Insets show enlarged views of selected abnormal chromosomes. Red arrows indicate examples of chromosome fusions and blue arrows indicate chromosome breaks.
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pgen-1003518-g005: Hat1 is essential for maintaining genome stability.A) Hat1+/+ and Hat1−/− MEFs were stained with either DAPI or α-γH2AX antibodies as indicated (left). Visible γH2AX foci were counted in 12 cells of each genotype (right). B) Metaphase spreads from Hat1+/+ and Hat1−/− MEFs were analyzed for chromosome number and the presence of breaks and fusions. The percentage of cells containing the indicated chromosomal abnormality is given. The number of spreads analyzed was 56 (Hat1+/+) and 112 (Hat1−/−). C) Metaphase spreads were generated from Hat1+/+ and Hat1−/− MEFs. Insets show enlarged views of selected abnormal chromosomes. Red arrows indicate examples of chromosome fusions and blue arrows indicate chromosome breaks.

Mentions: As loss of Hat1 resulted in sensitivity to DNA damage, we next explored whether Hat1 was also necessary for proper genome stability. One hallmark of genome instability is the presence of DNA damage in the absence of treatment with DNA damaging agents. Hat1+/+ cells showed undetectable levels of endogenous DNA damage, as measured by the presence of γ-H2AX foci (Figure 5A). In contrast, untreated Hat1−/− cells showed numerous γ-H2AX foci. An increase in γ-H2AX levels, both before and after DNA damage, in Hat1−/− MEFs was confirmed by Western blot analysis of whole cell extracts (Figure S3).


Histone acetyl transferase 1 is essential for mammalian development, genome stability, and the processing of newly synthesized histones H3 and H4.

Nagarajan P, Ge Z, Sirbu B, Doughty C, Agudelo Garcia PA, Schlederer M, Annunziato AT, Cortez D, Kenner L, Parthun MR - PLoS Genet. (2013)

Hat1 is essential for maintaining genome stability.A) Hat1+/+ and Hat1−/− MEFs were stained with either DAPI or α-γH2AX antibodies as indicated (left). Visible γH2AX foci were counted in 12 cells of each genotype (right). B) Metaphase spreads from Hat1+/+ and Hat1−/− MEFs were analyzed for chromosome number and the presence of breaks and fusions. The percentage of cells containing the indicated chromosomal abnormality is given. The number of spreads analyzed was 56 (Hat1+/+) and 112 (Hat1−/−). C) Metaphase spreads were generated from Hat1+/+ and Hat1−/− MEFs. Insets show enlarged views of selected abnormal chromosomes. Red arrows indicate examples of chromosome fusions and blue arrows indicate chromosome breaks.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3675013&req=5

pgen-1003518-g005: Hat1 is essential for maintaining genome stability.A) Hat1+/+ and Hat1−/− MEFs were stained with either DAPI or α-γH2AX antibodies as indicated (left). Visible γH2AX foci were counted in 12 cells of each genotype (right). B) Metaphase spreads from Hat1+/+ and Hat1−/− MEFs were analyzed for chromosome number and the presence of breaks and fusions. The percentage of cells containing the indicated chromosomal abnormality is given. The number of spreads analyzed was 56 (Hat1+/+) and 112 (Hat1−/−). C) Metaphase spreads were generated from Hat1+/+ and Hat1−/− MEFs. Insets show enlarged views of selected abnormal chromosomes. Red arrows indicate examples of chromosome fusions and blue arrows indicate chromosome breaks.
Mentions: As loss of Hat1 resulted in sensitivity to DNA damage, we next explored whether Hat1 was also necessary for proper genome stability. One hallmark of genome instability is the presence of DNA damage in the absence of treatment with DNA damaging agents. Hat1+/+ cells showed undetectable levels of endogenous DNA damage, as measured by the presence of γ-H2AX foci (Figure 5A). In contrast, untreated Hat1−/− cells showed numerous γ-H2AX foci. An increase in γ-H2AX levels, both before and after DNA damage, in Hat1−/− MEFs was confirmed by Western blot analysis of whole cell extracts (Figure S3).

Bottom Line: Murine Hat1 is essential for viability, as homozygous deletion of Hat1 results in neonatal lethality.The neonatal lethality is due to severe defects in lung development that result in less aeration and respiratory distress.Many of the Hat1(-/-) neonates also display significant craniofacial defects with abnormalities in the bones of the skull and jaw.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, OH, USA.

ABSTRACT
Histone acetyltransferase 1 is an evolutionarily conserved type B histone acetyltransferase that is thought to be responsible for the diacetylation of newly synthesized histone H4 on lysines 5 and 12 during chromatin assembly. To understand the function of this enzyme in a complex organism, we have constructed a conditional mouse knockout model of Hat1. Murine Hat1 is essential for viability, as homozygous deletion of Hat1 results in neonatal lethality. The lungs of embryos and pups genetically deficient in Hat1 were much less mature upon histological evaluation. The neonatal lethality is due to severe defects in lung development that result in less aeration and respiratory distress. Many of the Hat1(-/-) neonates also display significant craniofacial defects with abnormalities in the bones of the skull and jaw. Hat1(-/-) mouse embryonic fibroblasts (MEFs) are defective in cell proliferation and are sensitive to DNA damaging agents. In addition, the Hat1(-/-) MEFs display a marked increase in genome instability. Analysis of histone dynamics at sites of replication-coupled chromatin assembly demonstrates that Hat1 is not only responsible for the acetylation of newly synthesized histone H4 but is also required to maintain the acetylation of histone H3 on lysines 9, 18, and 27 during replication-coupled chromatin assembly.

Show MeSH
Related in: MedlinePlus